“They are so rare and so unique,” he told the Chicago Sun-Times. “If people really saw the significance of these, they will stand out next to all these other 50,000 meteorites" -- the number of known meteorites around the world.

One of the four meteorites embedded in limestone.

The golf ball-sized meteorites, which are set to go on display at the museum by year-end, are among only 100 such fossilized meteorites known to exist. They were recovered from a limestone quarry in southern Sweden.

The first fossil meteorite ever discovered was found in Sweden in 1952, and it took almost 30 years before it was identified as a meteorite.

According to Heck, researchers have only just now scratched the surface of determining the origin of the meteorites. So far, they think the meteorites may have fallen to Earth almost 500 million years ago as the remnants of a giant asteroid collision.